Why Use Our Products
BiteMeTM is an air-filled, bite block specifically designed to protect patient’s teeth and airway devices during general anaesthesia.
NoPressTM is a shield to protect eyes from externally applied pressure during general anaesthesia.
EyeProTM is a dressing designed to maintain eyelid closure during general anaesthesia.
The ASA Closed Claim Study found that eye injuries accounted for 3% of claims against anaesthetists. These injuries were most probably due to eye opening during anaesthesia, trauma or application of pressure to the eye1.
The NoPressTM has been designed to resist very high pressures (20-22 Newtons of force3)
Is Shielding the Eyes from Pressure Necessary?
Laterally positioned shoulder scope patient. Patient’s face is directly under surgeon’s hand.
In upper body surgery or prone/semi-prone positioning our patients are routinely draped and we have very limited access to inspect or touch their face. To cause eye globe morbidity a large pressure may be applied for a short period or, more easily missed, is the smaller pressure which is applied over a much longer time. Clearly, applying sustained pressure on the eye is the same as the risk from glaucoma, and often an exterior pressure is greatly in excess of that which might be internally generated. This risk of pressure injury is increased as we age2.
Throat (ORL), Dental, Maxillo-Facial, Upper Gastointestinal, Cardio-Thoracic, Neurosurgery, some Orthopaedics and Plastics or where the patient is supine or laterally positioned; there is an increased risk of accidental pressure being applied to an anaesthetised patient’s eyes1.
Once the patient is draped, surgical retractors, head supports, surgical assistants or the surgeons themselves may lean or rest on the eyes.
By decreasing eye injuries, all practitioners, their institutions and most importantly, their patients, will benefit.
Problems with Current Methods
Methods currently used to protect the eyes from pressure are sub-optimal.
Many practitioners or their assistants “construct” a device from two eyepads and tape. This takes time, costs money and provides a barrier to seeing the eyes and offers little protection (see photo).
There are other devices available but they often have separate compartments for each eye and this can make sizing difficult. The nature of these compartments has also led to severe eye injuries5.
Cost and Time Efficiency
Each minute of theatre time has been estimated to cost US $664. NoPressTM comes ready to use and its non-stick tabs allow easy and rapid removal of the backing sheet before applying.
Because the shield is transparent it makes accurate positioning very easy.
Accidental pressure applied to an eye globe may cause serious morbidity or permanent blindness. Follow-up care in relation to diagnosis and management of such an injury may be time consuming, lead to increased discharge times and have major economic ramifications for all those involved.
NoPressTM Benefits and Advantages
Patented design that allows flexion around nose and conformity to patient’s facial shape
Single plastic shield that transmits applied pressure around the patient’s bony orbital margins
No sharp down-facing edges which could injure underlying tissues if pressure is applied
Individually packaged in dust proof bag
Two non-stick tabs to allow easy placement, even when wearing gloves
3M biocompatible adhesive
Transparent shield which allows user to see patient’s eyes
Small holes to prevent condensation
1. Injuries associated with anaesthesia. A global perspective A. R. Aitkenhead* British Journal of Anaesthesia 95 (1): 95–109 (2005).
3. Bayly Group Formal Testing November 2015, Melbourne, Australia.
4. Shippert, RD 2005, ‘A study of time dependent operating room fees and how to save $100 000 by using time-saving products’, The American Journal of Cosmetic Surgery, vol. 22, no 1.
5. Visual Loss in a Prone-Positioned Spine Surgery Patient with the Head on a Foam Headrest and Goggles Covering the Eyes: An Old Complication with a New Mechanism Roth, S*; Tung, A*; Ksiazek, S† Anesthesia & Analgesia Volume 104(5), May 2007, pp 1185-1187.
Many injuries sustained during anaesthesia are due to human error and may be avoided through high standards of clinical practice. Ocular injury occurs during 0.1- 0.5 % of general anaesthetics when eyes are taped and is usually corneal in nature1,2. This incidence has been reported at 44% in one study of untaped eyes during general anaesthesia3.Eye injuries account for 2% of medico-legal claims against anaesthetists in Australia and United Kingdom1,3 and 3% in the USA4.
Affect of General Anaesthesia on Eyes
General anaesthesia reduces the tonic contraction of the orbicularis oculi muscle, causing lagophthalmos ie. the eyelids do not close fully in 60% of patients1.
In addition, general anaesthesia reduces tear production and tear-film stability, resulting in corneal epithelial drying and reduced lysosomal protection. The protection afforded by Bell’s phenomenon (in which the eyeball turns upwards during sleep, protecting the cornea) is also lost during general anaesthesia5.
Mechanism of Injury
Corneal abrasions are the most common injury; they are caused by direct trauma, exposure keratopathy3,6,7or chemical injury6,8.
An open eye increases the vulnerability of the cornea to direct trauma from objects such as face masks, laryngoscopes, identification badges, stethoscopes, surgical instruments, anaesthetic circuits, or drapes.
Exposure keratopathy refers to the drying of the cornea with subsequent epithelial breakdown9. When the cornea dries out it may stick to the eyelid and cause an abrasion when the eye reopens10.
Chemical injury can occur if cleaning solutions such as Betadine, chlorhexidine or alcohol are inadvertently spilt into the eye, such as when the face or mouth is being prepped for surgery2,3.
Therefore, the anaesthetist must ensure that the eyes are fully closed and remain closed throughout the procedure, in order to avoid exposure keratopathy. Seemingly trivial contact can result in corneal abrasion and the risk of this occurring is markedly increased if exposure keratopathy is already present3.
Corneal abrasions can be excruciatingly painful in the postoperative period, may hamper postoperative rehabilitation and may require ongoing ophthalmological review and after care. In extreme cases there may be partial or complete visual loss.
Methods to Prevent Eye Injuries
Methods to prevent perioperative corneal injuries include simple manual closure of the eyelids, taping the eyelids shut, use of eye ointment (although this is controversial, see below), bio-occlusive dressings and suture tarsorrhaphy. However, none of the protective strategies are completely effective; vigilance is always required ie. the eyes need to be inspected regularly throughout surgery to check they are closed1.
Problems with current methods
For many years, in most western countries, the eyes of patients undergoing general anaesthesia have been routinely taped or stuck down with adhesive dressings in an attempt to combat these problems.
Unfortunately many of the adhesives used on medical products today are temperature and time sensitive ie. their adhesive strength may increase or decrease when applied to a 37 degree Celsius body11 and the longer they are applied, the greater the variability in their adhesiveness. What may seem the perfect adhesive strength before application can change as the operation progresses; leading to failure of stick or “over stickiness”. In the former case, the eyelids may move apart and in the latter, may cause bruising, eyelid tears and eyelash removal.
Rolls of tapes are often “laying around” the operating theatre and may not be hygienically clean12. Most of these tapes are translucent and so it is not possible to see if the patient’s eyes are opened or closed throughout the case. It is not uncommon for the eyelids to move open as the case progresses, even with adhesive tapes stuck onto them.
In a practical sense, these medical tapes/dressings may be difficult to remove from a patient because their ends can become stuck flush with the skin.
As noted above, there have been several studies looking at the efficacy and safety of eye ointments/lubricants as adjuncts with tape or as a stand-alone management for intra-operative eye closure. Unfortunately many in common use have problems. Petroleum gel is flammable and is best avoided when electrocautery and open oxygen are to be used around the face. Preservative-free eye ointment is preferred, as preservative can cause corneal epithelial sloughing and conjunctival hyperemia8; they have been implicated in blurred vision in up to 75% of patients.
They do not protect from direct trauma5,13.
Adverse Outcomes Associated With Intra-operative Injuries
|Increased length of stay.||Due to ophthalmology consults required, associated infections and treatment13|
|Increased costs.||Due to increased length of stay, cost of treating the complications14|
|Pain and discomfort for patient.||Corneal abrasions are extremely painful for the patient and the treatment consists of drops and ointments applied in the eye which may cause discomfort for the patient13,14|
Studies have shown that the incidence of dental injuries associated with anaesthesia is around 1 in 1000 to 1 in 2000 i.e. (0.05 – 0.1%)3,4.
Why do we need to use a bite block?
In several series of closed claims data from multiple countries, dental damage is the most common claim made against anaesthetists and makes up 20 -30% of claims1,2.
Patients with poor dentition, reconstructive dental work or in their 50-70s are all at increased risk of dental damage3,5.
Multiple studies have shown that the maxillary incisors were at the highest risk for injury3.
14% of dental injuries occurred in PACU, after the patient had been handed over3.
As well as protecting the teeth, bite blocks also decrease the risk of damage to, or compression of, the airway device while still in the patient.
How does BiteMeTM differ from other bite blocks?
BiteMeTM is made of a very strong, but soft, plastic that resists the shear forces of a human bite very well.
The combination of the soft plastic surrounding a closed air-filled space means that when a patient bites down, there are two forces opposing the bite.
This means the BiteMe is has a spongey recoil and is therefore less likely to damage the teeth compared to a guedel airway; which have been shown to increase the risk of dental trauma3.
Many practitioners use rolled pieces of gauze as bite blocks, but these have to be “constructed”, may be difficult to insert, often are ineffective and cost more than most people think (average cost of 4 pieces of gauze, tape and time to construct = around 40 – 60c)
Air and plastic combination means less trauma to teeth
Plastic is food grade and safe
Easy to insert and remove
Highly visible in the mouth
Download the BiteMeTM brochure in the following languages.
- Ranum D, Ma H. Analysis of patient injury based on anesthesiology closed claims data from a major malpractice insurer. J Health Risk Manag 2014;34(2):31-42
- Chadwick RG, Lindsay SM. Dental injuries during general anaesthesia: can the dentist help the anaesthetist? Dent Update 1998;25(2):76-78
- Newland MC, Ellis SJ. Dental injury associated with anesthesia: a report of 161,687 anesthetics given over 14 years. J Clin Anesth 2007;19:339-345.
- Gaiser RR, Castro AD. The level of anesthesia resident training does not affect the risk of dental injury. Anesth Analg 1998;87:255-7
- Givol N, Gershtansky Y.Perianesthetic dental injuries: analysis of incident reports. J Clin Anesth 2004;16:173-176.